pub unsafe extern "C" fn glfwSetFramebufferSizeCallback(
window: *mut GLFWwindow,
cbfun: Option<extern "C" fn(*mut GLFWwindow, i32, i32)>,
) -> Option<extern "C" fn(*mut GLFWwindow, i32, i32)>pub unsafe extern "C" fn glfwSetFramebufferSizeCallback(
window: *mut GLFWwindow,
cbfun: Option<extern "C" fn(*mut GLFWwindow, i32, i32)>,
) -> Option<extern "C" fn(*mut GLFWwindow, i32, i32)>